Omega-3 and omega-6 fatty acids are both known to improve heart health and cognition. But they appear to have opposite effects when it comes to migraine pain.

Omega-3 and omega-6s are polyunsaturated fatty acids, and we cannot make them on our own — they need to be part of our diet. Omega-3 fatty acids are found in fish and shellfish, and omega-6 linoleic acid is found in vegetable oils and some nuts and seeds.

Omega-3 and omega-6 fatty acids are precursors to molecules called oxylipids that decrease (omega-3 fatty acids) or increase (omega-6 fatty acids) pain in preclinical migraine models. Researchers from the National Institute on Aging (NIA), the National Institute on Alcohol Abuse and Alcoholism (NIAAA) and the University of North Carolina wanted to see if a a diet high in omega-3 fatty acids and low in omega-6 linoleic acid — the H3-L6 diet — might be used to treat migraines in combination with medication.

The diet reduced the number of severe headache hours per day and the overall number of headache days per month.

They found the H3-L6 diet was particularly effective at reducing headaches.

“The reduction in headache days per month was similar to what we see with some medications,” Daisy Zamora, an adjunct assistant professor of psychiatry at the University of North Carolina, told TheDoctor. The results support recommending a diet high in omega-3 fatty acids to patients with migraines, according to an editorial accompanying the study by Rebecca Burch, an assistant professor of neurology at Harvard Medical School.

About 180 adults were enrolled in the 16-week study. Participants were randomly placed in either the H3-L6 diet; the H3 diet, a diet high in omega-3s with linoleic acid kept at typical levels for the American diet; or a control diet in which both omega-3s and linoleic acid were at typical levels.

Participants recorded their number of migraine days, the duration and intensity of their headaches and how often they needed to take pain medications during the study period. They also noted how migraines affected their social lives and their ability to function at work.

The high omega-3, low omega-6 diet reduced the total number of headache hours per day by 30 to 40 percent compared to the control diet. It also deceased the number of severe headache hours per day and the overall number of headache days per month. Blood samples from those assigned to the H3-L6 and H3 diets had lower levels of pain-related lipids compared to samples taken from the control group. However, participants randomized to the H3-L6 diet reported only small improvements in migraine-related quality of life, compared to participants in the other two groups.

The work is part of an ongoing effort by the UNC department of physical medicine and rehabilitation to develop techniques and interventions using dietary approaches to relieve pain, explained Chris Ramsden, a clinical investigator at the NIA and the NIAAA, and a co-author on the study, explained to TheDoctor. He and his team are currently doing a collaborative study in military personnel with post-traumatic headaches, and they are planning research in patients with other chronic pain conditions.

The study and a related editorial are published in The BMJ.